Add ux0:tai/nonpdrm.skprx (or ur0 for SD2Vita) under the *KERNEL section of your config.txt .
Once the refresh is complete, the Undertale bubble will appear on your home screen. 💡 Key Features on Vita NoNpDrm Guide: The cleanest Vita game backup method Undertale PS VITA (USA) (NoNpDrm)
Copy the Undertale game folder to your Vita's ux0:app/ directory via VitaShell using USB or FTP. Add ux0:tai/nonpdrm
In VitaShell, go to the home screen, press Triangle , and select Refresh LiveArea . go to the home screen